Drier promoter compositions

ABSTRACT

The present invention relates to a composition which comprises a zirconium salt of at least one organic carboxylic acid and an alkali metal or alkaline earth metal perborate. The compositions are useful in promoting the drying of ink compositions and particularly in printing inks used in the lithographic printing process.

FIELD OF THE INVENTION

The present invention relates to compositions of matter useful as drierpromoter compositions for coating compositions. More particularly, theinvention relates to water activated compositions which are useful forpromoting the drying of printing inks, and, in particular, printing inksused in the lithographic printing process.

BACKGROUND OF THE INVENTION

Protective and decorative coating compositions such as paints,varnishes, printing inks and enamels contain a film-forming base andother materials such as pigments, extenders, fillers, resins, solvents,thinners, plasticizers, etc. In order to decrease the drying time ofsuch coating compositions, it has been the practice to incorporatetherein various drying compositions which have typically been metalsalts of organic carboxylic acids such as manganese, lead, cobalt,calcium and iron salts of carboxylic acids such as naphthenic, oleicacid, linoleic acid, octanoic acid, etc. To be useful commercially as adrier, a metal salt should be stable for a long period on storage, andit should be essentially completely soluble in the hydrocarbon solventsor diluents ordinarily used in drier compositions as well as in dryingoils. A desirable feature of a drier composition is its ability toeffect an even drying throughout the thickness of the film.

In order to provide drier compositions which are capable of affectingmore uniform drying of films and coatings, drying compositionscomprising mixtures of transition metal salts of carboxylic acids suchas cobalt octoate, manganese octoate and various metal perborates suchas calcium perborate, have been utilized as curing systems for variouscoatings including pigmented and unpigmented varnishes includingpigmented varnish-ink for lithographic use. The use of mixtures ofcalcium perborate, manganese octoate and cobalt octoate as a curingsystem for varnish inks is described in Canadian Patent 1,190,987. TheCanadian patent describes methods and compositions for making sheetssuch as paper sheets or cards covered with superimposed layers of print,the lower of which comprises a "hidden" message which is masked from areader unless and until an upper coating is removed such as by abrasion,scratching or erasing.

SUMMARY OF THE INVENTION

The present invention relates to a drier promoter composition whichcomprises a zirconium salt of at least one organic carboxylic acid andan alkali metal or alkaline earth metal perborate. The promoters areuseful in ink compositions and particularly as promoters for dryingprinting inks used in the lithographic printing process.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The zirconium salts which are useful in the promoter compositions of theinvention preferably are salts of carboxylic acids or mixtures ofcarboxylic acids. The preparation of zirconium salts or organiccarboxylic acids is well known to those skilled in the art. At times,such salts have been referred to in the art as soaps. The salts or soapsof zirconium can be prepared as normal or basic salts or soaps byvarying the amount of metal reacted with the organic carboxylic acid andby other techniques used in the art to increase the amount of metalreacted with the carboxylic acid which results in overbased products. Abasic or overbased zirconium salt or soap is one that contains more thana stoichiometric amount of the metal in relation to the carboxylic acid.

The organic carboxylic acids used in the formation of the salts or soapscan be either natural or synthetic, aliphatic or aromatic acids ormixtures thereof. Examples of natural acids, although usually refined,include straight and branched chain carboxylic acids and mixtures suchas tall oil acids and cyclic carboxylic acids such as naphthenic acids.A variety of synthetic carboxylic acids, and particularly aliphaticcarboxylic acids or mixtures thereof are useful, and these generallycontain six or more carbon atoms.

The metal salts or soaps can be prepared by fusion or precipitationmethods. The soaps normally are prepared in an inert liquid medium suchas a hydrocarbon oil or solvent. The organic carboxylic acids generallywill have at least six carbon atoms and as many as 30 carbon atoms, butwhen more than one carboxylic acid is employed, carboxylic acidscontaining as little as two carbon atoms may be employed as one of theacids of the mixture. Examples of useful organic carboxylic acidsinclude acetic acid, propionic acid, butyric acid, isopentanoic acid,hexanoic acid, 2-ethylbutyric acid, nonanoic acid, decanoic acid,2-ethylhexanoic acid, isooctanoic acid, isononanoic acid, neodecanoicacid, lauric acid, palmitic acid, tall oil acids, stearic acid, oleicacid, linoleic acid, naphthenic acid, etc. Mixtures of these acids witheach other or the mixtures obtained after saponification of various oilscan be employed in the preparation of the zirconium soaps. The basicsalts or soaps are preferred since these contain higher amounts ofzirconium, and those salts and soaps containing even higher metalcontent, often referred to as "overbased" are particularly useful in theinvention. Accordingly, zirconium salts and soaps have been prepared andare known in the art containing various amounts of zirconium rangingfrom, for example, about 5% zirconium to about 30% zirconium or more.Useful zirconium soaps are described in, for example, U.S. Pat. Nos.2,739,902 and 3,046,153.

Specific examples of the zirconium salts or soaps which are useful inthe compositions of the invention include zirconium naphthenate,zirconium neodecanoate, zirconium tallate, zirconium 2-ethylhexanoate,etc. Examples of zirconium salts of a mixture of acids such as saltsdisclosed in British Patent 1,002,103, include zirconium naphthenateacetate (10% Zr); zirconium tallate propionate (10% Zr); etc. Mineralspirits solutions of zirconium salts are available from MooneyChemicals, Inc., Cleveland, Ohio 44113 under the general tradedesignations TEN-CEM, CEM-ALL, NAP-ALL, HEX-CEM, LIN-ALL and NEO-NAP.The zirconium content of these available salts ranges from about 5% toabout 30%. When desired, the mineral spirits may be stripped from thesalt and replaced by the desired amount of oleaginous liquid oflubricating viscosity such as a mineral oil. Alternatively, theoleaginous liquid may be added to the mineral spirits solution and themixture heated under vacuum to remove the mineral spirits.

Promoter compositions of the present invention also contain an alkalimetal or alkaline earth metal perborate. The perborates provide a sourceof oxygen below the surface and result in internal drying of the filmeven when the curable film is not exposed to air. The decomposition ofthe perborate to release oxygen is promoted by the cobalt and manganesedriers in the film as the ink picks up water during the printingprocess. The zirconium present in the composition is a rheology modifierand has some effect on surface (skin) drying. Thus, the combination ofthe zirconium salt and the metal perborate is effective in providingdesirable drying characteristics throughout the film. In one embodiment,the promoter compositions are free of metals of the first transitionseries such as manganese. Promoter compositions containing suchtransition metals, e.g., manganese perborate, are not as stable as thepromoter compositions of this invention which do not contain manganese.

Among the preferred alkali metal perborates are the sodium and potassiumperborates. Calcium and magnesium are preferred alkaline earth metalperborates with calcium being the most preferred of the metals.

The relative amounts of zirconium salt and metal perborate included inthe compositions of the present invention may vary over a wide range. Inone embodiment, the compositions may contain from about 10 to about 90%by weight of the zirconium salt and from about 10 to about 90% by weightof the metal perborate.

In another embodiment, the promoter compositions of the presentinvention will comprise, an inert diluent in addition to the zirconiumsalt and metal perborate. Although any inert diluent can be utilized,the diluent generally is an oleaginous liquid which may include naturalor synthetic oils, or mixtures thereof. Natural oils include animal oilsand vegetable oils (e.g., castor oil, lard oil) as well as liquidpetroleum oils and solvent-treated or acid-treated mineral lubricatingoils of the paraffinic, naphthenic or mixed paraffinic or naphthenictypes. Such mineral oils are a preferred diluent for the driercompositions of this invention. Useful mineral oils are available from avariety of sources.

When the promoter compositions of the present invention include adiluent, the compositions generally will comprise from about 5 to about45% by weight of the zirconium salt, from about 5 to about 45% by weightof the alkali metal or alkaline earth metal perborate, and from about 10to about 90% by weight of the organic diluent.

The relative amount of zirconium salt and metal perborate included inthe compositions of the present invention, whether an organic diluent ispresent or not, may be varied as desired by one skilled in the art.Generally, the amount of zirconium salt contained in the driercomposition should be an amount which is sufficient to interact with(wet out) the hydrophilic salts contained in the drier composition toprovide a stable slurry; increase the viscosity of the dispersion to adesired level; and contribute to the drying capabilities of thecomposition to the extent desired. In some embodiments, the driercompositions of the present invention may contain as little as 1 or 2%of the zirconium salt.

The compositions of the present invention may also contain otheradditives to provide desirable properties. For example, anhydrous boricacid may be included to interact with any atmospheric moisture which maycome into contact with the drier before use. Dispersants, stabilizersand thixotropes may also be included in the drier compositions. Anexample of a stabilizer-dispersant is sodium tripolyphosphate, and asilica filler such as HI SIL P-600 can be included in the compositionsas a thixotrope. These additional components may be included in thedrier composition in an amount from about 0.1 to about 10% by weight.

The compositions of the present invention may be prepared by mixing thecomponents in any order using an apparatus capable of reducing theparticles within the dispersion to a fine particle size such as about 10microns. For example, the composition may be prepared in a ball millwhere the components are mixed to a very fine particle size of less thanabout 20 microns, and preferably below about 10 microns.

The following examples illustrate the promoter compositions of thepresent invention. Unless otherwise indicated in the examples andelsewhere in the specification and claims, all parts and percentages areby weight, temperatures are in degrees centigrade and pressures are ator near atmospheric pressure.

    ______________________________________                                                             % Wt.                                                    ______________________________________                                        Example 1                                                                     Calcium perborate monohydrate                                                                        40                                                     Zirconium octanoate (18% zirconium)                                                                  40                                                     Mineral oil            20                                                     Example 2                                                                     Zirconium octoanate (24% zirconium)                                                                  14.0                                                   Sodium perborate monohydrate                                                                         25.5                                                   Anhydrous boric acid   7.7                                                    Sodium tripolyphosphate                                                                              5.4                                                    Fumed Silica           2.0                                                    Polypropylene glycol   1.8                                                    Mineral oil            43.6                                                   ______________________________________                                    

The compositions of the present invention are useful in a variety ofprinting inks, and, in particular, in printing inks used in thelithographic printer process. Printing inks for this purpose may includepigmented varnishes which may comprise one or more resins such asphenolic modified rosin ester, hydrocarbon resins, linseed-isophthalicalkyd resins, etc. Hydrocarbon plasticizers may be included to impartflexibility properties to the dried ink. Various drying oils such aslinseed oil, tung oil, etc., may be included in the inks to adjust theconsistency and tackiness of the surface. The inks also contain variousdrying or curing agents heavy metal-organic salts such as the manganeseand/or cobalt carboxylates. Examples of such curing agents which arecommonly used are manganese octanoate and cobalt octanoate. Gellingagents also may be included to adjust the consistency of the ink, andthese may include reaction products derived from unsaturated fattyacids. Thickeners such as fumed silica also may be incorporated into theprinting inks. Printing inks generally contain from about 15 to about30% by weight of pigment, the choice of pigment may be depended upon theintended use of the ink, and the desired color or colors.

The amount of the promoter composition of the present inventionincorporated into the printing inks also may be varied depending uponthe nature of the ink and the desired rate of drying. Normally, thecomposition of the present invention, such as the of Example 2, will beincluded in the ink compositions in amounts from about 0.5 to about 10%by weight, more generally, from about 1 to about 6 or 7% by weight.

The utility and advantage of the promoter compositions of this inventionis demonstrated in the following examples.

CONTROL-1

A printing ink is prepared comprising 200 parts of a red ink (No.S-1173, Multi Color); 1.5 parts of Cobalt LIN-ALL™ containing 6% cobalt(Mooney Chemicals, Inc.); 1.5 parts of Manganese LIN-ALL™ containing 6%manganese (Mooney Chemicals, Inc.); 0.6 part of methyl ethyl ketoximeand 4 parts of water.

CONTROL-2

To 25 parts of the ink of Control-1, 1.0 part of zirconium HEX-CEM™containing 18% zirconium (Mooney Chemicals, Inc.) is added.

EXAMPLE A

To 25 parts of the ink of Control-1, 1.0 part of the promotercomposition of Example 2 is added.

The drying times for the inks prepared in Example A and the two controlexamples are determined as follows. Scrapedowns of the compositions areprepared on an ink test pad (Leneta Form 3NT-1 or equivalent) using ascrapedown bar while applying sufficient pressure to obtain a uniformlythin film. The thin film is then covered with onionskin paper with theglazed side down. The covered scrapedown with the onionskin paper on topis placed on a glass panel in an environmental chamber which has beenequilibrated to the desired temperature and humidity which are generally77° F. and 50% relative humidity. Gardner Recorders are centered overthe ink film while insuring that the rear leg holds the onionskin paperdown. Weights are used to maximize the offset and to minimize itsdisturbance by air currents. The recorders are operated for 12 hours.The covered scrapedowns are then removed from the chamber and theonionskin paper is peeled away from the scrapedown. The start and end ofthe scribe on the onionskin paper is marked, and using the Gardner12-hour template, the drying times are measured and recorded to tenthsof an hour. The drying times for three inks (duplicates) are shown inthe following table.

    ______________________________________                                        Sample       Dry Times (hours)                                                                           Average                                            ______________________________________                                        Control-1    12+, 12+      12+                                                Control-2    10.1, 10.6    10.4                                               Example A    0.7, 0.9      0.8                                                ______________________________________                                    

As can be seen from the above results, the use of the promotercomposition of this invention (Example A) significantly reduces thedrying time.

While the invention has been explained in relation to its preferredembodiments, it is to be understood that various modifications thereofwill become apparent to those skilled in the art upon reading thespecification. Therefore, it is to be understood that the inventiondisclosed herein is intended to cover such modifications as fall withinthe scope of the appended claims.

What is claimed is:
 1. A drier promoter composition comprising azirconium salt of at least one organic carboxylic acid containing from 6to about 30 carbon atoms and an alkali metal perborate.
 2. Thecomposition of claim 1 wherein the organic carboxylic acid is at leastone aliphatic or alicyclic monocarboxylic acid containing from about 6to about 30 carbon atoms.
 3. The composition of claim 1 wherein theorganic carboxylic acids contain from about 6 to about 12 carbon atoms.4. The composition of claim 1 which is free of metals of the firsttransition series.
 5. The composition of claim 1 comprising about 10 toabout 90% of the zirconium salt and about 10 to about 90% of the metalperborate.
 6. The composition of claim 1 also containing an inertdiluent.
 7. The composition of claim 6 wherein the inert diluent is amineral oil.
 8. The composition of claim 1 wherein the alkali metalperborate is sodium perborate.
 9. A water-activatable drier promotercomposition for printing inks comprising from about 5 to about 45% byweight of a zirconium salt of at least one organic carboxylic acidcontaining from 6 to about 24 carbon atoms, from about 5 to about 45% byweight of an alkali metal perborate, and from about 10 to about 90% byweight of an organic diluent.
 10. The composition of claim 9 wherein themetal perborate is sodium perborate.
 11. The composition of claim 9which is free of metals of the first transition series.
 12. Thecomposition of claim 9 wherein the organic carboxylic acids contain from6 to 12 carbon atoms.
 13. The composition of claim 9 wherein the organicdiluent is a mineral oil.